The pneumococcal typing system and pneumococcal surveillance

Summary The Danish pneumococcal typing system, its development and its applicability are reviewed. Variations in the prevalence of pneumococcal serotypes with time and geographical area are examined. While the percentage of types in the currently available 14-valent pneumococcal polysaccharide vaccine is uniformly high in different series, typing surveillance studies must be performed, to ensure continued optimal vaccine compositions.